日本曲霉产生的黑麦酮酸F对玉米的化感作用

日本曲霉（Aspergillus japonicus)是土壤和谷物种子表面的一种常见真菌。研究结果表明。日本曲霉所产生的大量黑麦酮酸F(SAF)对玉米(Zea mays)有很强的化感作用,低浓度显著促进玉米幼苗生长,高浓度则抑制．在0．0375mmol·L^-1SAF下,玉米幼苗根长增长31．7％,根数量增加13．2％,根活力提高4．73倍,并促进玉米对P、K、Ca、Mg、S等5种营养元素的吸收．高浓度SAF(0．3mmol·L^-1)下玉米根活力受抑制(72．1％),根对N、P、K、Ca、Mg、Fe等营养元素的吸收也受抑制.0．6mmol·L^-1的SAF下根完全失去活力,电镜观察表明,有SAF的情况下玉米叶绿体片层结构模糊、混乱,双层膜不完整。     

铜处理对菠菜幼苗矿质营养吸收和细胞超微结构的影响

土壤重金属积累严重影响植物生长和生态系统平衡,探寻植物对重金属的耐性机理尤为重要.菠菜可能具有一定的耐铜性,但Cu对其矿质元素吸收、细胞超微结构等方面的耐性机理尚不明确.本研究以菠菜幼苗为研究对象,通过盆栽试验,探究不同浓度铜处理对菠菜幼苗生长、矿质元素吸收、叶片细胞超微结构等指标的影响.结果表明: 100 mg·L^-1 CuSO₄处理浓度时,菠菜幼苗根Cu²⁺积累量小于地上部,其根系生长量增加,地上部生长量稍有下降,继续增加铜处理浓度,植物体各器官生长参数均呈下降趋势.低浓度铜处理时(<400 mg·L^-1 CuSO₄),菠菜幼苗叶N、K、Ca、Mg、Fe含量增加,P含量减少;根N、P、K含量减少,Ca、Mg、Fe含量增加;叶片细胞内各细胞器清晰可见,基粒片层排列仍较为整齐,叶绿体内外膜完整.高浓度铜处理时(>600 mg·L^-1 CuSO₄),菠菜幼苗叶N含量增加,P、K、Ca、Mg、Fe含量减少;根N、P、K、Ca、Mg、Fe含量均减少;叶片细胞内叶绿体变圆,叶绿体膜变薄,基质、基粒片层变少,层堆积高度下降,细胞核解体,液泡、细胞壁中有黑色小点分布,可能是大量Cu²⁺聚集导致细胞内膨压增大所致.低浓度铜处理并未对菠菜幼苗的生长生理特性产生明显的负面影响,而高浓度铜处理并未终止菠菜幼苗的生长.说明菠菜幼苗具有一定的耐铜性.     

纯化腐植酸对低氮胁迫下黄瓜幼苗生长及养分吸收的影响

以黄瓜‘新泰密刺’、‘津优1号’为供试品种,研究沙培条件下不同浓度(0、50、100、150、200 mg·L^-1)纯化腐植酸(PHA)浇灌对低氮胁迫(1 mmol·L^-1 NO₃^-)下黄瓜幼苗生长及养分吸收的影响.结果表明: 在较低N供应条件下,沙培浇灌PHA可显著增加黄瓜幼苗的根总长、根表面积及根尖数,增大根体积,促进黄瓜幼苗株高和茎粗生长,增大叶面积;显著提高黄瓜幼苗叶片中脯氨酸及可溶性糖含量;促进N素以及P、K、Ca、Mg、Fe元素的吸收.由参试两黄瓜品种对低氮胁迫下PHA处理响应效果来看,不同品种的某些性状对PHA处理浓度的敏感程度稍有差异,综合结果显示,施用100～150 mg·L^-1PHA可显著促进两品种幼苗生长及养分吸收.     

硝普钠对缺铁和硝酸盐胁迫下番茄幼苗生长及生理特性的影响

采用营养液培养方法,研究外源NO供体(硝普钠,SNP)对缺铁和硝酸盐胁迫番茄幼苗生长、养分吸收及抗氧化酶活性的影响.结果表明: 处理7 d后,缺铁使番茄幼苗生长受到抑制,叶绿素a、b、类萝卜素含量显著降低,出现明显失绿症状;降低叶片中超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)的活性,电解质渗漏率、丙二醛含量明显增加,脯氨酸和可溶性糖含量变化不显著,幼苗叶片和根中N、P、K、Ca、Mg、Fe含量比对照处理有不同程度的减少.硝酸盐和缺铁双重胁迫对番茄幼苗生长抑制加剧,叶绿素a、b、类萝卜素含量、SOD、POD和CAT活性显著降低,电解质渗漏率、脯氨酸、可溶性糖和丙二醛含量明显增加;番茄幼苗叶片和根中N、P、Mg、Fe含量显著减少,而K、Ca含量显著增加. 与不添加处理相比,添加0.1 mmol·L^-1 SNP处理使胁迫番茄幼苗的生长抑制明显缓解.添加0.1 mmol·L^-1 SF(亚铁氰化钠)的处理在SOD、POD和CAT等指标上也表现出一定程度的缓解或促进作用,但其他生理指标没有表现出缓解或促进作用,原因是SF中也含有铁离子.     

落叶松幼苗碳素和氮素的获取与分配对供氮水平的响应

落叶松(Larix gmelinii)是中国东北林区最重要的工业用材树种,而且在北温带森林中具有重要的生态学意义。落叶松的种植区域内气温低、冬季长,氮素矿化速度低,供氮不足常常成为落叶松生长的限制因素。为揭示落叶松生长与氮素营养的关系,采用沙培法设置了1、4、8和16 mmol·L^-1 4个供氮水平,研究了不同供氮条件下落叶松一年生幼苗对碳和氮的获取与分配的规律。结果显示,落叶松幼苗的生物量、全株氮浓度、氮含量、比氮吸收速率均随供氮水平的增加而升高,叶重比(LWR)、茎重比(SWR)及叶氮比(LNR)、茎氮比(SNR)亦随供氮水平的增加而增加,而根重比(RWR)和根氮比(RNR)则随供氮水平的增加而降低。当供氮水平从1 mmol·L^-1增加至8 mmol·L^-1时,落叶松幼苗相对生长速率呈线性增加,而全株氮生产力几乎未受供氮水平的影响;当供氮水平从8 mmol·L^-1增加至16 mmol·L^-1时,全株相对生长速率不再增加,全株氮生产力则显著下降。与全株氮生产力的变化不同,落叶松幼苗的叶氮生产力与供氮水平呈负相关。     

镉胁迫对秋华柳根系活力及其Ca、Mg、Mn、Zn、Fe积累的影响

以秋华柳为试验材料,采用水培试验方式,设置CK(0 mg·L^-1 Cd²⁺)、T₁(2 mg·L^-1 Cd²⁺)、T₂(10 mg·L^-1Cd²⁺)、T₃(20 mg·L^-1Cd²⁺)、T₄(50 mg·L^-1Cd²⁺)5种镉处理浓度,通过对秋华柳根系活力,叶、韧皮部、木质部和根部的镉含量,以及Ca、Mg、Mn、Zn、Fe 5种常规金属元素含量的测定,研究了不同浓度镉胁迫下秋华柳根系活力及Ca、Mg、Mn、Zn、Fe 等金属元素含量的变化.结果表明:1)秋华柳根系活力随着镉处理浓度的增加而逐渐下降,当镉浓度≥10 mg·L^-1时,根系活力与对照相比显著下降.2)随着镉处理浓度的增加,秋华柳叶中Fe的积累受到显著抑制;韧皮部Mg、Mn、Fe的积累受到显著抑制;木质部Ca、Mg、Mn、Zn、Fe 等5种常规金属元素的积累无显著性差异;根部5种常规金属元素的吸收和积累受到显著抑制,表现出镉对其他金属元素积累的拮抗作用.其中,50 mg·L^-1的镉胁迫下,根部Zn的积累量降幅最大,受Cd的抑制最明显.3)各处理组Fe的转移系数与对照相比均无显著性差异;Ca、Mg、Mn、Zn的转移系数均高于对照,且在一定的镉处理水平上差异显著.4)镉胁迫下,秋华柳根部镉的积累量与Ca的积累量呈显著负相关,与其他4种常规金属元素的积累量呈极显著负相关,说明根部常规金属元素的变化可作为秋华柳受镉毒害程度的指示之一.     

新疆胀果甘草幼苗耐盐性及对NaCl胁迫的离子响应

以盐碱荒漠草甸药用植物胀果甘草(Glycyrrhiza inflata)为材料, 采用水培法研究了盐处理(50、100、200、300 mmol·L^-1NaCl) 28天后幼苗株高、生物量、含水量、根粗、甘草酸含量和不同器官的离子含量及离子的选择吸收、运输能力, 并对丙二醛、脯氨酸含量进行测定, 以确定其耐盐范围及耐盐方式。结果表明, 低盐浓度对胀果甘草幼苗生长无显著影响, 只有较高盐浓度(≥200 mmol·L^-1 NaCl)使幼苗总生物量、株高、甘草酸含量显著降低; 根据耐盐系数与盐浓度的拟合方程, 确定适宜幼苗生长的盐浓度范围为0-278.17 mmol·L^-1。随盐浓度上升, 植株选择性吸收K⁺、Ca²⁺、Mg²⁺, 而抑制Na⁺进入体内, 幼苗对进入植株体内的Na⁺在不同盐浓度下采取了不同的分配策略, 低盐浓度下(0-100 mmol·L^-1), 植株体内Na⁺主要积累在根中, 避免了叶中Na⁺的过多积累, 其盐适应机制以耐盐方式为主; 高盐浓度下(≥200 mmol·L^-1 NaCl), Na⁺主要积累在下部叶, 并通过叶片脱落的方式带走体内的盐分, 其盐适应机制以避盐方式为主。盐胁迫下, 幼苗能促进K⁺而抑制Na⁺向上部叶的运输, 使上部叶拒Na喜K, 维持了较高的K⁺/Na⁺比值, 有利于幼苗生长; 同时, 地下根系能通过积累Ca²⁺、Mg²⁺和合成脯氨酸、甘草酸, 以提高渗透调节能力, 缓解Na⁺毒害, 使根的生长不受影响, 有利于保证幼苗在盐环境中吸收维持生长的必要养分, 这是胀果甘草幼苗具有较强耐盐性的原因。以上结果说明, 胀果甘草幼苗通过对盐离子的吸收和运输调控、离子区域化和渗透调节, 以耐盐和避盐两种方式适应盐碱荒漠环境。     

外源褪黑素与钙离子互作对高温胁迫下黄瓜幼苗过氧化伤害的缓解效应

为了探明褪黑素(MT)和钙离子(Ca²⁺)在调控植物耐热性中是否存在互作关系,以黄瓜幼苗为试材,分析了内源MT和Ca²⁺对高温胁迫的响应;并通过叶面喷施100 μmol·L^-1 MT、10 mmol·L^-1 CaCl₂、3 mmol·L^-1乙二醇二乙醚二胺四乙酸(EGTA,Ca²⁺螯合剂)+100 μmol·L^-1 MT、0.05 mmol·L^-1氯丙嗪(钙调素拮抗剂,CPZ)+100 μmol·L^-1 MT、100 μmol·L^-1氯苯丙氨酸(p-CPA,MT合成抑制剂)+10 mmol·L^-1 CaCl₂和去离子水(H₂O),研究高温下(42/32 ℃)外源MT和Ca²⁺对黄瓜幼苗活性氧积累、抗氧化系统及热激转录因子(HSF)和热激蛋白(HSPs)等的影响。结果表明: 黄瓜幼苗内源MT和Ca²⁺均受高温胁迫诱导;外源MT可上调常温下钙调素蛋白(CaM)、钙依赖蛋白激酶(CDPK5)、钙调磷酸酶B类蛋白(CBL3)、CBL结合蛋白激酶(CIPK2)mRNA表达;CaCl₂处理的MT合成关键基因色氨酸脱羧酶(TDC)、5-羟色胺-N-乙酰转移酶(SNAT)和N-乙酰-5-羟色胺甲基转移酶(ASMT)水平也显著升高,MT含量快速增加。MT和CaCl₂可显著增强高温下黄瓜的抗氧化能力,减少活性氧(ROS)积累,同时上调HSF7、HSP70.1和HSP70.11 mRNA表达,从而减轻高温胁迫引起的过氧化伤害,植株热害症状明显减轻,热害指数和电解质渗漏率显著降低。加入EGTA和CPZ后,MT对黄瓜幼苗抗氧化能力和热激蛋白表达的促进效应明显减弱,Ca²⁺对高温下黄瓜幼苗过氧化伤害的缓解效应也被p-CPA逆转。可见,MT和Ca²⁺均可诱导黄瓜幼苗的耐热性,二者在热胁迫信号转导过程中存在互作关系。     

3,4-二羟基苯乙酮胁迫对天山云杉种子萌发过程中内源植物激素含量变化的影响

3,4-二羟基苯乙酮(DHAP)是天山云杉(Picea schrenkiana ssp. tianschanica)叶和凋落物中存在的主要自毒物质, 是导致天山云杉林天然更新障碍的原因之一。为了解释自毒物质发生作用的生理机制, 该文设计多个浓度梯度的DHAP溶液处理天山云杉种子, 以发芽率和发芽势为种子萌发参数, 运用反相超高效液相色谱(UPLC)分析技术, 检测了种子萌发过程中内源植物激素玉米素(ZT)、赤霉素(GA₃)、吲哚乙酸(IAA)和脱落酸(ABA)含量水平的变化。研究结果表明: DHAP处理对天山云杉种子萌发影响具有浓度效应, 表现为5.0 mmol·L^-1 > 0.1 mmol·L^-1 > 1.0 mmol·L^-1 >对照, 即5.0 mmol·L^-1 DHAP处理组对种子萌发的抑制作用最强、0.1 mmol·L^-1 DHAP处理组次之、1.0 mmol·L^-1 DHAP处理组最弱; DHAP处理组的种子内源ZT、GA₃浓度水平降低, ABA含量升高, GA₃浓度峰值出现时间延迟, IAA浓度在高浓度(5.0 mmol·L^-1 DHAP)处理组短时间内(3-6天)过量积累, 1.0和5.0 mmol·L^-1 DHAP处理组的种子内源ABA浓度峰值出现时间延迟; DHAP处理种子萌发1-6天时, ZT/(GA₃+IAA)比值降低, IAA/ZT、ABA/ZT比值增大; ABA/(ZT + GA₃ + IAA)比值在0.1 mmol·L^-1 DHAP处理组增大, 在5.0 mmol·L^-1 DHAP处理组降低。DHAP处理引发种子内源激素含量水平及激素含量间比值变化, 可能是抑制、延迟天山云杉种子萌发的主要原因。     

外源褪黑素对盐胁迫下银杏幼苗渗透调节和抗氧化能力的影响

以4年生银杏幼苗为材料,进行不同浓度盐胁迫(50、100、200 mmol·L^-1)处理,叶片喷施和土壤浇灌外源褪黑素溶液(0、0.02、0.1、0.5 mmol·L^-1),研究外源褪黑素对盐胁迫下银杏幼苗渗透调节和抗氧化能力的影响。结果表明：盐胁迫显著抑制银杏幼苗渗透调节和抗氧化能力,而在盐胁迫下施用适宜浓度(0.02、0.1 mmol·L^-1)的外源褪黑素能够促进植株生长,降低电解质外渗率,减少黄酮和丙二醛含量,促进叶片中过氧化物酶、超氧化物歧化酶(SOD)活性的提高,但高浓度(0.5 mmol·L^-1)外源褪黑素会进一步加剧氧化胁迫和渗透胁迫。0.02和0.1 mmol·L^-1外源褪黑素处理缓解了盐胁迫下银杏幼苗的渗透胁迫和氧化胁迫,且0.02 mmol·L^-1外源褪黑素处理对盐胁迫缓解效果最佳。地径、枝条宽度、枝条长度、电解质外渗率、SOD活性和黄酮含量可作为快速鉴定银杏受盐胁迫程度的关键指标。     

Coccystes undoxylophus

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Prosthecium species with Stegonsporium anamorphs on Acer

Data from microscopic morphology, single-spore cultures, and DNA analyses of teleomorphs and anamorphs support the recognition of five species of Prosthecium with Stegonsporium anamorphs on Acer: P. acerinum sp. nov., the teleomorph of S. acerinum; P. acerophilum comb. nov., formerly known as Dictyoporthe acerophila; P. galeatum comb. nov., originally described as Massaria galeata; P. opalus sp. nov.; and P. pyriforme sp. nov., the teleomorph of S. pyriforme s. str. The morphology of both type specimens and freshly collected material was investigated. The teleomorphs have brown ellipsoidal ascospores with five distosepta and often a longitudinal distoseptum. The anamorphs of all species described here belong to Stegonsporium; their connection to the Prosthecium teleomorphs was demonstrated by morphology and DNA sequences of single spore cultures derived from both ascospores and conidia. The anamorphs and teleomorphs of all five Prosthecium species are described and illustrated by LM images, and a key to these species is provided. As perceived from this work, S. pyriforme is restricted to Europe and does not occur in North America, whereas S. acerinum is restricted to North America, not found in Europe. The host associations given in the literature are revised and evidence is provided that only A. opalus, A. pseudoplatanus, and A. saccharum are confirmed hosts of Prosthecium with Stegonsporium anamorphs. Molecular phylogenetic analyses of tef1, ITS rDNA, and partial nuLSU rDNA sequences confirm that the species with Stegonsporium anamorphs are closely related to P. ellipsosporum, the generic type species. Stilbospora macrosperma is confirmed as the anamorph of P. ellipsosporum by DNA data of single spore isolates obtained from both ascospores and conidia.     

UeberAquila pennata undminuta

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Ester production in E. coli and C. acetobutylicum

Genetic engineering has improved the product yield of a variety of compounds by overexpressing, inactivating, or introducing new genes in microbial systems. The production of flavor-enhancing ester compounds is an emerging area of heterologous gene expression for desired product yield in Escherichia coli. Isoamyl acetate, butyl acetate, ethyl acetate, and butyl butyrate are reported here to be produced by expressing Saccharomyces cerevisiae genes ATF1 or ATF2 and the strawberry gene SAAT in E. coli when the appropriate substrates are provided. Increasing the concentration of alcohol added to the reaction generally resulted in increased ester production. ATF1 expression was found to produce more isoamyl acetate and butyl acetate than ATF2 expression or SAAT expression in the strains and culture conditions examined. Additionally, SAAT expression resulted in greater isoamyl acetate and butyl acetate production than ATF2 expression. Butyl butyrate is produced by cell-free extracts of E. coli harboring SAAT but not ATF1 or ATF2.     

Chemical composition, in situ ruminal degradability and post-ruminal disappearance of dry matter and crude protein from the halophytic plants Kochia scoparia, Atriplex dimorphostegia, Suaeda arcuata and Gamanthus gamacarpus

Samples of Kochia (K. scoparia), Atriplex (A. dimorphostegia), Suaeda (S. arcuata) and Gamanthus (G. gamacarpus) were collected and analyzed for chemical composition including crude protein (CP), ether extract (EE), ash, neutral detergent fiber (NDFom), acid detergent fiber (ADFom), non-protein N (NPN), Ca, P, Na, K, Cl, Mg, Fe, Cu and Se. In addition, in situ ruminal degradability and post-ruminal disappearance of dry matter (DM) and CP of the samples using a mobile bag technique were determined. Results indicate that the chemical composition of Kochia and Atriplex was notably different from those of Suaeda and Gamanthus. All of these halophytic plants had high concentrations of Na, K, Cl, Cu and Se, and low levels of Ca, P and Mg. The rapidly degradable fractions of DM and CP (g/g) of Kochia (0.31 and 0.35, respectively) and Atriplex (0.39 and 0.50, respectively) were lower than for Suaeda (0.53 and 0.55, respectively) and Gamanthus (0.56 and 0.66, respectively). Ruminal DM and CP disappearance of Kochia (444 and 517 g/kg, respectively) and Atriplex (472 and 529 g/kg, respectively) were lower (P<0.05) than those of Suaeda (553 and 577 g/kg, respectively) and Gamanthus (663 and 677 g/kg, respectively) (P<0.05) using the mobile bag technique. Suaeda had the lowest (P<0.05) NDFom and ADFom disappearance (214 and 232 g/kg, respectively) in the rumen. Kochia scoparia and Atriplex dimorphostegia have more beneficial chemical nutritive components and digestible values versus Suaeda arcuata and Gamanthus gamacarpus.     

Aquila pennata undminuta

Ohne Zusammenfassung     

Effects of MULTIFOLIATE-PINNA, AFILA, TENDRIL-LESS and UNIFOLIATA genes on leafblade architecture in Pisum sativum

In order to dissect the genetic regulation of leafblade morphogenesis, 16 genotypes of pea, constructed by combining the wild-type and mutant alleles of MFP, AF, TL and UNI genes, were quantitatively phenotyped. The morphological features of the three domains of leafblades of four genotypes, unknown earlier, were described. All the genotypes were found to differ in leafblade morphology. It was evident that MFP and TL functions acted as repressor of pinna ramification, in the distal domain. These functions, with and without interaction with UNI, also repressed the ramification of proximal pinnae in the absence of AF function. The expression of MFP and TL required UNI function. AF function was found to control leafblade architecture multifariously. The earlier identified role of AF as a repressor of UNI in the proximal domain was confirmed. Negative control of AF on the UNI-dependent pinna ramification in the distal domain was revealed. It was found that AF establishes a boundary between proximal and distal domains and activates formation of leaflet pinnae in the proximal domain.     

The role of the genesnrf EFG andccmFH in cytochromec biosynthesis inEscherichia coli

It has been suggested that two groups ofEscherichia coli genes, theccm genes located in the 47-min region and thenrfEFG genes in the 92-min region of the chromosome, are involved in cytochromec biosynthesis during anaerobic growth. The involvement of the products of these genes in cytochromec synthesis, assembly and secretion has now been investigated. Despite their similarity to other bacterial cytochromec assembly proteins, NrfE, F and G were found not to be required for the biosynthesis of any of thec-type cytochromes inE. coli. Furthermore, these proteins were not required for the secretion of the periplasmic cytochromes, cytochromec ₅₅₀ and cytochromec ₅₅₂, or for the correct targeting of the NapC and NrfB cytochromes to the cytoplasmic membrane. NrfE and NrfG are required for formate-dependent nitrite reduction (the Nrf pathway), which involves at least twoc-type cytochromes, cytochromec ₅₅₂ and NrfB, but NrfF is not essential for this pathway. Genes similar tonrfE, nrfF andnrfG are present in theE. coli nap-ccm locus at minute 47. CcmF is similar to NrfE, the N-terminal region of CcmH is similar to NrfF and the C-terminal portion of CcmH is similar to NrfG. In contrast to NrfF, the N-terminal, NrfF-like portion of CcmH is essential for the synthesis of allc-type cytochromes. Conversely, the NrfG-like C-terminal region of CcmH is not essential for cytochromec biosynthesis. The data are consistent with proposals from this and other laboratories that CcmF and CcmH form part of a haem lyase complex required to attach haemc to C-X-X-C-H haem-binding domains. In contrast, NrfE and NrfG are proposed to fulfill a more specialised role in the assembly of the formate-dependent nitrite reductase.